Liquid crystalline compounds, liquid crystal compositions containing the same and use thereof

ABSTRACT

Liquid crystalline compounds having an optically active γ-lactone ring of the general formula (A): ##STR1## wherein R 1  is a group selected from the class consisting of ##STR2## n and e are each independently 0 or 1, R 3  is an alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms, said alkyl and alkenyl groups having each optionally one or more asymmetric carbon atoms, X and Y are each hydrogen atom, a halogen atom or a cyano group, R 2  is an alkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbon atoms, said alkyl and alkenyl groups having each optionally one or more asymmetric carbon atoms, and * means an asymmetric carbon atom, a liquid crystal composition containing the same and an element for opto-electronics devices comprising the liquid crystal composition.

This application is a divisional of Ser. No. 07/557,777, filed Jul. 26,1990, now U.S. Pat. No. 5,338,482.

This invention relates to liquid crystalline compounds, liquid crystalcompositions containing the same and use thereof as an element fordisplay devices or an element for opto-electronics devices. The liquidcrystalline compounds of this invention include not only the compoundswhich can exhibit the liquid crystal phase by themselves but also thecompounds which do not exhibit the liquid crystal phase alone but areuseful as a component of liquid crystal compositions.

PRIOR ART

Liquid crystals have widely been used as a material for display devices,where a TN (Twisted Nematic) type display system is usually employed.This TN display system has such advantages that it has less electricconsumption, it gives less eye fatigue because it is a receptor type,and the like, but on the other hand, this system is disadvantageous inthat the driving force is very weak because it is driven mainly on thebasis of anisotropy of dielectric constant and it is slow in responsespeed, and hence, this system can not be applied to the devices whichrequire high response speed.

Liquid crystal having ferroelectricity has first been found by R. B.Meyer et al. in 1975 (cf. J. Physique, 36, L-69, 1975). This liquidcrystal is driven by a comparatively large force derived fromspontaneous polarization and shows extremely high response speed and hasalso good memory. Owing to such excellent properties, the ferroelectricliquid crystal has been noticed as a new type of display element. Inorder to exhibit the ferroelectricity, the liquid crystalline compoundsshould show chiral smectic C phase (SmC* phase) and thus should containat least one asymmetric carbon atom in the molecule. It is alsonecessary to have a dipole moment in the direction vertical to the longaxis of the molecule.

A ferroelectric liquid crystal DOBAMBC synthesized by Meyer et al. hasthe following formula: ##STR3## and satisfies the above conditions, butit contains a Schiff base and hence is chemically unstable and show sucha low spontaneous polarization as 3×10⁻⁹ C/cm². Since then, there havebeen synthesized many ferroelectric liquid crystalline compounds, butany practically useful compound having sufficiently high response speedhas never been found.

Among the known ferroelectric liquid crystalline compounds, DOBA-1-MBCwhich has the asymmetric carbon atom at the position nearer to thecarbonyl group than in DOBAMBC and has the following formula: ##STR4##shows a spontaneous polarization of 5×10⁻⁸ C/cm² which is larger thanthat of DOBAMBC. It is assumed that this will be caused by the followingdifference. That is, the asymmetric carbon atoms and the dipole whichare important factors for the appearance of ferroelectricity arepositioned close to each other, and thereby, the free rotation of thedipole moiety of molecule is depressed and then the orientation of thedipole is increased. Thus, it is assumed that the known ferroelectricliquid crystalline compounds can not give satisfactory spontaneouspolarization and high response speed because the asymmetric carbon atomhaving an inhibitory action of the free rotation of the molecule ispresent on the linear chain in the known ferroelectric liquidcrystalline compounds and hence the free rotation of the molecule cannot completely be inhibited and the dipole moiety can not be fixed.

U.S. Pat. No. 4,909,957 issued on Mar. 20, 1990 (corresponding EuropeanPatent Publication No. 306919 published on Mar. 15, 1989) disclosesliquid crystalline compounds having an optically active γ-lactone ringof the formula: ##STR5## wherein R₁ is a group selected from the groupconsisting of ##STR6## n and e are each independently 0 or 1, R₃ is analkyl group having 1 to 15 carbon atoms, R₂ is a group of the formula:--(CO)m--R₄ wherein m is 0 or 1 and R₄ is hydrogen atom or an alkylgroup having 1 to 15 carbon atoms, and * means an asymmetric carbonatom. The liquid crystalline compound disclosed therein have acomparatively high melting point. It is also known that a liquidcrystalline compound having a lower melting point can advantageously beincorporated in a larger amount in a liquid crystal composition.

SUMMARY DESCRIPTION OF THE INVENTION

Under the circumstances, the present inventors have intensively studiedas to inhibition of free rotation of dipole moiety in the conventionalferroelectric liquid crystalline compounds and as to improvement of theabove liquid crystalline compound (I) and have found that the freerotation can be inhibited by providing a compound wherein the asymmetriccarbon atom is contained in a 5-membered lactone ring, by which therecan be obtained a chemically stable liquid crystalline compound havingferroelectricity and that the introduction of a methyl group at the2-position of the lactone ring lowers a melting point of the compoundand it thereby can be incorporated into a liquid crystal composition inan increased amount without deteriorating the chemical stability andferroelectricity of the composition.

An object of the invention is to provide a novel ferroelectric liquidcrystalline compound which is chemically stable and is useful as anelement for display devices or an element for opto-electronics devices.Another object of the invention is to provide liquid crystallinecompounds having an optically active γ-lactone ring in the moleculewherein one or two asymmetric carbon atoms are present in the 5-memberedlactone ring. A further object of the invention is to provide a liquidcrystal composition containing at least one kind of the novel liquidcrystalline compounds. A still further object of the invention is toprovide an element for opto-electronics devices comprising thecomposition. These and other objects and advantages of the inventionwill be apparent to those skilled in the art from the followingdescription.

DETAILED DESCRIPTION OF THE INVENTION

The novel liquid crystalline compounds of the invention are compoundshaving an optically active γ-lactone ring and having the followinggeneral formula (A): ##STR7## wherein R¹ is a group selected from thegroup consisting of ##STR8## n and e are each independently 0 or 1, R³is an alkyl group having 1 to 15 carbon atoms or an alkenyl group having2 to 15 carbon atoms, said alkyl and alkenyl groups having eachoptionally one or more asymmetric carbon atoms, X and Y are eachhydrogen atom, a halogen atom or a cyano group, R² is an alkyl grouphaving 1 to 15 carbon atoms or an alkenyl group having 2 to 15 carbonatoms, said alkyl and alkenyl groups having each optionally one or moreasymmetric carbon atoms, and * means an asymmetric carbon atom.

In the specification, the term "alkyl group" for R² and R³ includesmethyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl,n-nonyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl,n-pentadecyl, isopropyl, t-butyl, 2-methylpropyl, 1-methylpropyl,3-methylbutyl, 2-methylbutyl, 1-methylbutyl, 4-methylpentyl,3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 5-methylhexyl,4-methylhexyl, 3-methylhexyl, 2-methylhexyl, 1-methylhexyl,6-methylheptyl, 5-methylheptyl, 4-methylheptyl, 3-methylheptyl,2-methylheptyl, 1-methylheptyl, 7-methyloctyl, 6-methyloctyl,5-methyloctyl, 4-methyloctyl, 3-methyloctyl, 2-methyloctyl,1-methyloctyl, 8-methylnonyl, 7-methylnonyl, 6-methylnonyl,5-methylnonyl, 4-methylnonyl, 3-methylnonyl, 2-methylnonyl,1-methylnonyl, 3,7-dimethyloctyl, 3,7,11-trimethyldodecyl, and the like.

The term "alkenyl" for R² and R³ includes a linear alkenyl such asvinyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl,decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl,etc. and a branched chain alkenyl such as 1-methylpropenyl,2-methylpropenyl, 3-methylpropenyl, 4-methylpropenyl, etc.

The novel compounds of this invention contain a carbonyl group within a5-membered ring and one or two asymmetric carbon atoms on the ring as amoiety having a dipole moment as an origin of ferroelectricity, andhence, the free rotation at this moiety is inhibited and thereby thedipole moiety is directed to one direction, which is effective forenlarging the spontaneous polarization and for increasing the responsespeed. Further, the substitution at the benzene ring of R¹ in theformula (A) with a halogen atom or a cyano group allows lowering amelting point of the compound of the invention, broadening thetemperature range of the chiral smectic C (SmC*) phase at the lowertemperature side, enlarging a chilt angle and increasing a spontaneouspolarization. In addition, the introduction of a cyano group isadvantageous in that it provides a compound having a large negativeanisotropy of the dielectric constant which is necessary for effectivelydriving the ferroelectric liquid crystal.

In the liquid crystalline compounds (A) of this invention, when R² ismethyl group, only one asymmetric carbon atom is contained, but when R²is a group other than a methyl group, two asymmetric carbon atoms arecontained in the γ-lactone ring and hence there are present two kinds ofdiastereomer. These are all suitable for inhibition of free rotation ofthe dipole moiety, and they are used as a liquid crystal alone or in amixture of two or more thereof.

The compounds (A) of the invention can be prepared by a process whichcomprises reacting an optically active γ-lactone compound of the generalformula (B): ##STR9## wherein R¹, R² and the symbol * are the same asR¹, R² and * in the formula (A), with a methyl halide (e.g. CH₃ I) underbasic conditions. That is, the compound of the formula (B) is reactedwith 1 to 1.5 equivalents of a base to give an enolate anion of thecompound (B), which is then reacted with 1 to 1.5 equivalents of amethyl halide. The base used therein includes lithium diisopropylamide,sodium diisopropylamide, potassium diisopropylamide, lithium1,1,1,3,3,3-hexamethyldisilazide, sodium1,1,1,3,3,3-hexamethyldisilazide, potassium1,1,1,3,3,3-hexamethyldisilazide, lithium1,1,1,3,3,3-hexaethyldisilazide, sodium 1,1,1,3,3,3-hexaethyldisilazide,potassium 1,1,1,3,3,3-hexaethyldisilazide, potassium t-butoxide, and thelike.

The above reaction is carried out in an organic solvent. The organicsolvent is preferably t-butyl alcohol when the base is potassiumt-butoxide. When the base is other than potassium t-butoxide, theorganic solvent is preferably ethers such as tetrahydrofuran, ethylether, dimethoxyethane, diethyleneglycol dimethyl ether, dioxane, etc.;aprotic solvents such as dimethylformamide, dimethyl sulfoxide,dimethylacetamide, hexamethylphosphoric triamide, etc.; or a mixedsolvent thereof.

The reaction is usually carried out at the reaction temperature of 30°to 90° C. for 15 minutes to 5 hours when the base is potassiumt-butoxide. In case a base other than potassium t-butoxide is employed,the reaction is usually carried out at -80° to 30° C. and completesimmediately or within at least 2 hours although the reaction temperaturemay vary depending on the kind of the base used therein.

The starting compound (B) can be prepared by reacting an opticallyactive glycidyl ether of the general formula (C): ##STR10## wherein R¹and * are the same as R¹ and * in the formula (A), with a ketoesterderivative of malonate a of the general formula (D): ##STR11## whereinR⁴ is hydrogen atom or an alkyl group having 1 to 15 carbon atoms and R⁵is a lower alkyl group having 1 to 4 carbon atoms, in the presence of abase in an organic solvent. That is, the compound (B) can be prepared byreacting under reflux the compound (C) with 1 to 5 equivalents of thecompound (D) in the presence of 1 to 5 equivalents of a base in anorganic solvent for 1.5 to 24 hours. The base used therein includesalkali metal alkoxides (e.g. sodium methoxide, sodium ethoxide,potassium t-butoxide, etc.), alkali metal hydrides (e.g. sodium hydride,lithium hydride, etc.), and alkyl alkali metals (e.g. n-butyllithium,etc.), and the organic solvent includes alcohols (e.g. methanol,ethanol, t-butyl alcohol, etc.), ethers (e.g. tetrahydrofuran, diethylether, dimethoxyethane, diethylene glycol dimethyl ether, dioxane,etc.), aprotic polar solvents (e.g. dimethylformamide,dimethylsulfoxide, hexamethylphosphoric triamide, etc.), and a mixtureof these solvents.

The starting optically active glycidyl ether (C) can be prepared by aprocess as shown in the following reaction scheme: ##STR12## wherein R¹and the symbol * are the same as R¹ and * in the formula (A).

That is, a phenol derivative of the formula R¹ OH is reacted with anoptically active epichlorohydrin in the presence of a base. Theoptically active epichlorohydrin is preferably used in an amount of 1 to10 equivalents to the phenol derivative, and the base is preferably usedin an amount of 1 to 5 equivalents to the phenol derivative. The baseincludes alkali metal hydroxides or alkoxides, such as sodium hydroxide,potassium hydroxide, potassium t-butoxide, and the like. The abovereaction may proceed smoothly without any catalyst, but may be carriedout in the presence of a catalyst. The catalyst includes quaternaryammonium halides, such as benzyltriethylammonium chloride,benzyltriethylammonium bromide, benzyltrimethylammonium chloride,benzyltrimethylammonium bromide, etc. and is used in an amount of 0.01to 0.1 equivalent to the phenol derivative. An excess amount of theoptically active epichlorohydrin may be used as the solvent, but thereis preferably used a suitable polar solvent such as dimethylformamide,dimethylsulfoxide, dimethylacetamide, acetonitrile, t-butyl alcohol, andwater. The reaction is usually carried out at a temperature of 50° to80° C. for 0.5 to 3 hours.

Alternatively, the optically active glycidyl ether (C) may also beprepared by reacting the phenol derivative of the formula R¹ OH with anoptically active epichlorohydrin in the presence of an amine (e.g.morpholine, piperidine, pyridine, etc.) of 0.1 to 0.5 equivalent to thephenol derivative and subjecting the resulting optically activechlorohydrin derivative to cyclization reaction with 1 to 5 equivalentsof a base, such as an alkali metal hydroxide, carbonate or alkoxide(e.g. sodium hydroxide, potassium hydroxide, potassium carbonate, sodiumcarbonate, potassium t-butoxide, etc.). The latter process is carriedout in two steps but is advantageous in that the extraction of theproduct can easily be done. This reaction is usually carried out at atemperature of 50° to 80° C. for 3 to 24 hours.

When a racemic epichlorohydrin is used in the above reaction, there isobtained a glycidyl ether in the form of a racemic mixture. The startingoptically active epichlorohydrin can be prepared in a high purity by theprocesses as described in Japanese Patent First Publication (Kokai) Nos.132196/1986 and 6697/1987 (as to R isomer) and by the process asdescribed in Japanese Patent Application No. 283393/1987 (as to Sisomer).

Besides, the starting phenol derivative used for the preparation of thecompound (C) can be prepared by the processes as shown in the followingReaction Schemes-I to -XI, wherein R³ is the same as R³ in the formula(A), R^(3') is an alkyl group having a carbon atom one smaller than thatin R³, X is a halogen atom, Ph in Reaction Scheme-VI means phenyl, R' inReaction Scheme-VI is a lower alkyl group having 1 to 4 carbon atoms andTs in Reaction Scheme-X means p-toluenesulfonyl group.

That is, 4-(4-trans-alkylcyclohexyl)phenols,4-(4-alkyloxyphenyl)phenols, and 4-(4-alkylphenyl)phenols are preparedby the known processes as shown in Reaction Schemes-I, -II and -III,respectively. ##STR13##

Besides, 4-(5-alkyl-2-pyrimidinyl)phenols and4-(5-alkyloxy-2-pyrimidinyl)phenols are prepared by the processes asshown in the following Reaction Schemes-IV and -V, respectively, whichare disclosed in Japanese Patent First Publication (Kokai) Nos.189274/1986 and DE 144,409. ##STR14##

Moreover, 4-[5-(4-alkyloxyphenyl)-2-pyrimidinyl]phenols and4-[5-(4-alkylphenyl)-2-pyrimidinyl]phenols are prepared by the processesas shown in the following Reaction Scheme-VI. ##STR15##

According to the process of Reaction Scheme-VI, Compound (E) is preparedby protecting the hydroxy group of p-hydroxybenzonitrile with a benzylgroup and converting the cyano group thereof into amidine hydrochloridein a usual manner. Separately, p-hydroxyphenylacetic acid is esterifiedwith a lower alcohol, and the phenolic hydroxy group is alkylated withan alkyl halide, alkyl p-toluenesulfonate or alkyl methanesulfonate,followed by reacting with diethyl carbonate in the presence of a base togive diethyl malonate derivative (G).

The amidine hydrochloride (E) is condensed with the diethyl malonatederivative (G) in the presence of a base such as alkali metal alkoxides(e.g. sodium ethoxide, sodium methoxide, etc.), followed by reactingwith phosphorus oxychloride in the presence of a base such as organicamines (e.g. N,N-diethylaniline, pyridine,4-(N,N-dimethylamino)pyridine, etc.), and the resulting compound isreduced with hydrogen gas in the presence of Pd-C catalyst to give thedesired 4-[5-(4-alkyloxyphenyl)-2-pyrimidinyl]phenol (I).

In the above process, when a diethyl p-alkylphenylmalonate (F) is usedinstead of the diethyl malonate derivative (G) and the compound (E) andthe compound (F) are reacted like in the reaction of the compound (E)and the compound (G), there is prepared4-[5-(4-alkylphenyl)-2-pyrimidinyl]phenol (H).

The diethyl p-alkylphenylmalonate (F) can be prepared by subjecting ap-alkylacetophenone to a Willgerodt reaction, esterifying the resultingphenylacetic acid derivative with a lower alcohol, and condensing theresultant with diethyl carbonate.

The starting phenol derivative wherein the benzene ring has asubstituent of a halogen atom or a cyano group can be prepared byconventional processes as shown in the following Reaction Schemes-VII toXI. ##STR16##

The liquid crystal composition of this invention may be obtained bymixing at least one compound (A) as prepared above with a chiral ornon-chiral liquid crystal or a mixture thereof.

The chiral or non-chiral liquid crystal employed in the liquid crystalcomposition of this invention is not particularly limited but may be anyconventional chiral or non-chiral liquid crystal which shows chiralsmectic C phase after mixing with the compound (A).

The conventional liquid crystal includes those described in e.g.Flussige Kristalle in Tabellen I, VEB Deutscher Verlag furGrundstoffindustrie, Leipzig, 1974; Flussige Kristalle in Tabellen II,VEB Deutscher Verlag fur Grundstoffindustrie, Leipzig, 1984.

Typical example of the above chiral or non-chiral liquid crystalincludes the compound of the general formula (J): ##STR17## wherein E, Fand G are each independently a 6-membered ring selected from the groupconsisting of: ##STR18## the hydrogen atom(s) in the 6-membered ringbeing optionally substituted with a halogen atom, cyano group or nitrogroup; a is 0 or 1; W, K, L and M are each a single bond or a groupselected from the group consisting of ##STR19## provided that K is asingle bond when a=0; R⁶ and R⁷ are each independently a straight chainor branched chain alkyl group having 1 to 15 carbon atoms, which maycontain one or more asymmetric carbon atoms.

Particularly suitable examples of the chiral or non-chiral liquidcrystal are a compound of the formula (J-1): ##STR20## wherein R⁸ and R⁹are the same or different and are each a straight chain or branchedchain alkyl group having 1 to 15 carbon atoms or a straight chain orbranched chain alkoxy group having 1 to 15 carbon atoms, said alkyl andalkoxy groups having optionally one or more asymmetric carbon atoms, anda compound of the formula (J-2): ##STR21## wherein R⁸ and R⁹ are asdefined above, A is ##STR22## and k and i are independently 0 or 1, butk+i≠2.

The liquid crytal composition of the invention comprises preferably onepart by weight of a compound of the formula (A) and 3 to 999 parts byweight of a compound of the formula (J).

The liquid crystal composition of this invention is useful for preparinga liquid crystal cell of an electrically controlled birefrigence mode orguest-host mode, which is prepared by attaching a transparent electrodeto the liquid crystal composition of this invention, sandwiching theresultant electrode-attached liquid crystal composition with two sheetsof glass plate which is surface-treated for orientation with a polymer(e.g. polyethylene, polyester, nylon, polyvinyl alcohol, polyimide,etc.), and providing a polarizer. The liquid crystalline compounds (A)and the racemic compounds of this invention may be added to otheroptically active liquid crystalline compounds in order to regulate thehelical pitch thereof.

The liquid crystalline compounds of this invention have excellent heatstability and light stability, and the optically active compounds haveexcellent properties as ferroelectric liquid crystal. The liquidcrystalline compounds of this invention are also useful for thefollowing utilities.

(1) Additives for TN (Twisted Nematic) type or STN (Super TwistedNematic) type liquid crystals in order to inhibit occurrence of reversedomain.

(2) Display element utilizing cholesteric-nematic phase transfer effects(cf. J. J. Wysoki, A. Adams and W. Haas; Phys. Rev. Lett., 20, 1024,1968).

(3) Display element utilizing White-Taylor type guest host effects (cf.D. L. White and G. N. Taylor; J. Appl. Phys., 45, 4718, 1974).

(4) Notch filter or band-pass filter utilizing selective scatteringeffects by fixing the cholesteric phase in matrix (cf. F. J. Kahn; Appl.Phys. Lett., 18, 231, 1971).

(5) Circularly polarized light beam splitter utilizing circularlypolarized light characteristics of the cholesteric phase (cf. S. D.Jacob; SPIE. 37, 98, 1981).

This invention is illustrated by the following Preparations andExamples, but should not be construed to be limited thereto.

In Examples, the positions of R and S in the optically active compounds(A) of this invention are shown by the position numbers in the followingformula: ##STR23##

The phase transfer temperature in Examples was measured by DSC(Differential Scanning Colorimetry) and a polarizing microscope.Besides, the symbols in the phase transfer temperature mean:

C: Crystalline phase

SmA: Smectic A phase

SmC: Smectic C phase

SmC*: Chiral smectic C phase

Sml: Non-identified smectic phase other than SmA, SmC and SmC*.

N: Nematic phase

N*: Chiral nematic phase

I: Isotropic liquid

The chiral smectic C phase (SmC*) was further confirmed by measuringdielectric constant thereof.

PREPARATION OF PHENOL DERIVATIVES Preparation 1 Preparation of4-[5-(4-n-octyloxyphenyl)-2pyrimidinyl]phenol

i) Preparation of 4-benzyloxyphenylamidine hydrochloride:

4-Cyanophenol (95.2 g), benzyl chloride (127 g) and potassium carbonate(138 g) are refluxed in acetone (160 ml) for 5 hours. The product isseparated by filtration, concentrated under reduced pressure, andthereto is added benzene. The mixture is washed with water, and benzeneis distilled off under reduced pressure to give 4-benzyloxybenzonitrile(141.38 g). The 4-benzyloxybenzonitrile (141 g) is dissolved in benzene(338 ml) and thereto is added ethanol (270 ml), and the mixture iscooled to 0° C. Into the resulting slurry is bubbled hydrogen chloridegas (36 liters) with stirring, and thereafter, the temperature is raisedto 25° C., and the mixture is allowed to stand for 2 days. The reactionmixture is concentrated under reduced pressure until 1/3 volume, and tothe concentrated mixture is added ether. The precipitated crystals areseparated by suction filtration to give an imide ester (183 g).

The above-obtained imide ester (183 g) is mixed with ethanol (270 ml) togive a slurry, and thereto is added a solution of ammonia (60.75 g) inethanol (405 ml). After allowing the mixture to stand at roomtemperature for 2 days, the solvent is distilled off under reducedpressure to give 4-benzyloxyphenylamidine hydrochloride (164.5 g).

NMR (DMSO-d₆) δ: 5.19 (2H, s), 7.17 (2H, d, J=9.0 Hz), 7.35 (5H, s),7.86 (2H, d).

ii) Preparation of diethyl 4-n-octyloxyphenylmalonate:

4-Hydroxyphenylacetic acid (50.0 g) is dissolved in ethanol (400 ml) andthereto is added conc. sulfuric acid (0.5 ml). The mixture is refluxedwith stirring, and ethanol is distilled off to give ethyl4-hydroxyphenylacetate (60 g).

The ethyl 4-hydroxyphenylacetate (59 g) and sodium ethoxide (22.4 g) aredissolved in ethanol (150 ml) and thereto is added n-octyl bromide (63.5g), and the mixture is refluxed for 3 hours and concentrated underreduced pressure, and thereto is added ethyl acetate to dissolve theoily substance. The mixture is washed with water, dried over anhydrousmagnesium sulfate, distilled under reduced pressure to remove ethylacetate, and further distilled under reduced pressure to give ethyl4-n-octyloxyphenylacetate (79.6 g, b.p. 179° C./0.1 mmHg).

The obtained ethyl 4-n-octyloxyphenylacetate (79 g), ethanol (140 ml),diethyl carbonate (300 ml) and sodium ethoxide (19.3 g) are mixed, andthe mixture is heated with stirring while ethanol is distilling off. Thereaction mixture is transferred into ice water and is acidified withhydrochloric acid. The organic layer is separated and the solvent isdistilled off to give diethyl 4-n-octyloxyphenylmalonate (91.6 g).

NMR (CDCl₃) δ: 0.5-2.0 (21H, m), 3.90 (2H, t, J=6.0 Hz), 4.16 (4H, q,J=7.2 Hz), 4.52 (1H, s), 6.80 (2H, d, J=9.0 Hz), 7.26 (2H, d, J=9.0 Hz).

iii) Preparation of 4-[5-(4-n-octyloxyphenyl)-2-pyrimidinyl]phenol:

4-Benzyloxyphenylamidine hydrochloride (65.6 g) and diethyl4-n-octyloxyphenylmalonate (91.0 g) are dissolved in methanol (500 ml)and thereto is added sodium methoxide (44.8 g), and the mixture isrefluxed with stirring for 9 hours. After cooling, the reaction mixtureis acidified with sulfuric acid, and the precipitated crystals areseparated by suction filtration to give yellow crystals (77.7 g).

The above yellow crystals (77 g), phosphorus oxychloride (310 ml) andN,N-diethylaniline (46.5 ml) are mixed and refluxed with stirring for 26hours. The excess phosphorus oxychloride is distilled off under reducedpressure, and the residue is transferred into ice-water and extractedwith ether. The extract is washed with water and distilled to removeether to give a crude product (70 g). The product is recrystallized fromether to give a compound (21 g) of the following formula: ##STR24##

NMR (CDCl₃) δ: 0.4-2.1 (15H, m), 3.99 (2H, t, J=6.0 Hz), 5.09 (2H, s),6.7-7.5 (11H, m), 8.38 (2H, d, J=9.0 Hz).

The colorless crystals obtained above (19.8 g), ethanol (757 ml),magnesium oxide (11.4 g), water (57 ml) and 10% Pd-C (4 g) are heatedwith stirring at 60° C. under hydrogen atmosphere until a theoreticalamount of hydrogen is absorbed. The reaction mixture is filtered withsuction, and the filtrate is concentrated to give the desired4-[5-(4-n-octyloxyphenyl)-2-pyrimidinyl]phenol (7.7 g), m.p. 137° C.

NMR (CDCl₃) δ: 0.5-2.1 (15H, m), 4.00 (2H, t, J=6.0 Hz), 6.92 (2H, d,J=9.0 Hz), 7.01 (2H, d, J=9.0 Hz), 7.50 (2H, d, J=9.0 Hz), 8.30 (2H, d,J=9.0 Hz), 8.94 (2H, s).

PREPARATION OF THE COMPOUNDS (C) Preparation 2

The starting phenol derivative (2.50 g) of the following formula:##STR25## and R-(-)-epichlorohydrin (chemical purity: 98.5% or more,optical purity: 99% or more, 4.25 g) and benzyltriethylammonium chloride(20 mg) are dissolved in dimethylformamide (3 ml) and thereto is addeddropwise 24 wt. % aqueous sodium hydroxide (1.2 equivalent) at 60° C.After reacting at the same temperature for 40 minutes, the reactionmixture is cooled to room temperature and extracted with ether. Theextract is distilled under reduced pressure to remove the solvent. Theresidue is purified by silica gel chromatography to give S isomer ofglycidyl ether (1.62 g) of the following formula: ##STR26##

m.p. 90° C.

[α]_(D) ²⁵ =+4.44° (c=1.01, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.50-3.00 (19H, m), 3.10-3.50 (1H, m), 3.80-4.30 (2H, m),6.75-7.60 (8H, m).

Preparation 3

The starting phenol derivative (5.28 g) of the following formula: -##STR27## and S-(-)-epichlorohydrin (chemical purity: 98.5% or more,optical purity: 99% or more, 11.55 g), potassium t-butoxide (3.00 g) andt-butyl alcohol (45 ml) are mixed and the mixture is stirred at 60° C.for 3 hours. The reaction mixture is distilled under reduced pressure toremove the solvent and the residue is extracted with chloroform. Theextract is distilled under reduced pressure to remove the solvent. Theresidue is purified by silica gel chromatography to give the R isomer ofthe glycidyl ether (5.82 g) of the following formula: ##STR28##

[α]_(D) ³¹ =-5.71° (c=1.66, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.60-2.50 (17H, m), 2.60-2.95 (2H, m), 3.15-3.60 (1H, m),3.80-4.30 (2H, m), 6.76 (2H, d, J=8.4Hz), 7.07 (2H, d, J=8.4Hz).

Preparation 4

A mixture of the starting phenol derivative (10 g) of the followingformula: ##STR29## the same R-(-)-epichlorohydrin (16.07 g) as used inPreparation 2, 20 wt. % aqueous sodium hydroxide (7.33 g) anddimethylformamide (20 ml) is heated with stirring at 60°-70° C. for onehour. The reaction mixture is cooled and thereto is added water. Themixture is extracted with chloroform to obtain a crude product (11.67g). The crude product is purified by silica gel chromatography to givethe S isomer of the glycidyl ether (9.07 g) of the following formula:##STR30##

m.p. 74° C.

[α]_(D) ²⁴ =+1.66° (c=1.02, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.5-2.2 (15H, m), 2.6-3.0 (2H, m), 3.1-3.7 (1H, m),3.8-4.4 (4H, m), 6.95 (2H, d, J=9.0 Hz), 8.26 (2H, d, J=9.0 Hz), 8.36(2H, s).

Preparation 5

A mixture of the starting phenol derivative (7.44 g) of the followingformula: ##STR31## as prepared in Preparation 1, the sameR-(-)-epichlorohydrin (9.16 g) as used in Preparation 2, 50 wt. %aqueous sodium hydroxide (1.74 g) and dimethylformamide (77 ml) isstirred at 60°-70° C. for 3 hours. The reaction mixture is cooled andthereto is added water, and the mixture is extracted withdichloromethane. The extracted product is purified by silica gelchromatography to give the S isomer of the glycidyl ether (6.90 g) ofthe following formula: ##STR32##

m.p. 198° C.

[α]_(D) ²⁵ =+0.95° (c=1.04, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.6-2.1 (15H, m), 2.6-3.0 (2H, m), 3.2-3.5 (1H, m),3.8-4.5 (2H, m), 6.99 (4H, d, J=9.0 Hz), 7.50 (2H, d, J=9.0 Hz), 8.40(2H, d, J=9.0 Hz), 8.90 (2H, s).

PREPARATION OF THE COMPOUNDS (B) Preparation 6

The optically active glycidyl ether prepared in Preparation 3, i.e.(R)-2,3-epoxypropyl 4-(trans-4-n-propylcyclohexyl)phenyl ether (406 mg),potassium t-butoxide (181 mg), dimethyl n-nonylmalonate (666 mg) andt-butyl alcohol (3 ml) are mixed, and the mixture is refluxed withstirring for 2 hours. The reaction mixture is cooled to room temperatureand thereto is added dropwise 4N hydrochloric acid until pH 1. Themixture is then extracted three times with chloroform, and the extractis washed once with saturated saline solution and distilled underreduced pressure to remove the solvent. The residue is purified bysilica gel chromatography to give γ-lactone derivatives, (2R, 4R) isomer(79 mg) and (2S, 4R) isomer (153 mg) of the following formulae:

(2R, 4R) isomer: ##STR33##

Phase transfer temperature: ##STR34##

[α]_(D) ³² =-31.45° (c=1.43, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.6-3.0 (39H, m), 4.0-4.2 (2H, m), 4.4-4.95 (1H, m), 6.76(2H, d, J=8.0 Hz), 7.10 (2H, d, J=8.0 Hz)

IR (KBr): 1762 cm⁻¹.

(2S, 4R) isomer: ##STR35##

Phase transfer temperature: ##STR36##

[α]_(D) ²⁸ =-27.82° (c=1.03, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.65-3.0 (39H, m), 4.0-4.2 (2H, m), 4.6-5.0 (1H, m), 6.76(2H, d, J=8.0 Hz), 7.10 (2H, d, J=8.0 Hz)

IR (KBr): 1762 cm⁻¹.

Preparation 7

The S isomer of glycidyl ether prepared in Preparation 2 (370 mg),diethyl n-propylmalonate (442 mg), potassium t-butoxide (134 mg) andt-butyl alcohol (3 ml) are mixed, and the mixture is refluxed withstirring for 10 hours. The reaction mixture is cooled to roomtemperature and thereto is added dropwise 4N hydrochloric acid untilpH 1. The mixture is washed with water and methanol to give whitecrystals. The product is separated and purified by silica gelchromatography to give γ-lactone derivatives, (2S, 4S) isomer (240 mg)and (2R, 4S) isomer (140 mg) of the following formulae:

(2S, 4S) isomer: ##STR37##

Phase transfer temperature: ##STR38##

[α]_(D) ²⁶ =+32.67° (c=1.081, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.70-3.00 (27H, m), 4.00-4.25 (2H, m), 4.40-4.85 (1H, m),6.60-7.60 (8H, m)

IR (KBr): 1762 cm⁻¹.

(2R, 4S) isomer: ##STR39##

Phase transfer temperature: ##STR40##

[α]_(D) ²⁶ =+22.50° (c=0.504, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.70-3.00 (27H, m), 4.00-4.25 (2H, m), 4.50-5.00 (1H, m),6.60-7.60 (8H, m)

IR (KBr): 1762 cm⁻¹.

Preparation 8

The S isomer of glycidyl ether prepared in Preparation 5 (518 mg),dimethyl n-pentylmalonate (940 mg) and potassium t-butoxide (269 mg) aredissolved in dimethylformamide (5 ml) and t-butyl alcohol (5 ml), andthe mixture is heated with stirring at 90° C. for 5 hours. After thereaction, the reaction mixture is treated in the same manner asdescribed in Preparation 7 to give γ-lactone derivatives (690 mg) of thefollowing formulae. The product is a mixture of diastereomers and ispurified by silica gel chromatography to give (2S, 4S) isomer and (2R,4S) isomer.

(2S, 4S) isomer: ##STR41##

Phase transfer temperature: ##STR42##

NMR (CDCl₃) δ: 0.4-3.0 (29H, m), 3.7-4.3 (4H, m), 4.71 (1H, m), 7.00(4H, d, J=9.0 Hz), 7.50 (2H, d, J=9.0 Hz), 8.39 (2H, d, J=9.0 Hz), 8.89(2H, s)

IR (nujol): 1778 cm⁻¹.

(2R, 4S) isomer: ##STR43##

Phase transfer temperature: ##STR44##

NMR (CDCl₃) δ: 0.4-3.0 (29H, m), 3.7-4.3 (4H, m), 4.82 (1H, m), 7.00(4H, d, J=9.0 Hz), 7.50 (2H, d, J=9.0 Hz), 8.39 (2H, d, J=9.0 Hz), 8.85(2H, s)

IR (nujol): 1778 cm⁻¹.

Preparation 9

The S isomer of glycidyl ether prepared in Preparation 4 (1.0 g),dimethyl n-heptylmalonate (1.267 g) and potassium t-butoxide (63 mg) aredissolved in dimethylformamide (10 ml) and t-butyl alcohol (10 ml), andthe mixture is heated with stirring at 90° C. for 2 hours. After thereaction, the reaction mixture is treated in the same manner asdescribed in Preparation 7 to give γ-lactone derivatives (705 mg). Theproduct is a mixture of diastereomers and is purified by silica gelchromatography to give (2S, 4S) isomer and (2R, 4S) isomer.

(2S, 4S) isomer: ##STR45##

Phase transfer temperature: ##STR46##

NMR (CDCl₃) δ: 0.4-3.1 (33H, m), 3.9-4.3 (4H, m), 4.66 (1H, m), 6.92(2H, d, J=9.0 Hz), 8.25 (2H, d, J=9.0 Hz), 8.35 (2H, s)

IR (nujol): 1776 cm⁻¹.

(2R, 4S) isomer: ##STR47##

Phase transfer temperature: ##STR48##

NMR (CDCl₃) δ: 0.4-3.1 (33H, m), 3.9-4.3 (4H, m), 4.77 (1H, m), 6.92(2H, d, J=9.0 Hz), 8.25 (2H, d, J=9.0 Hz), 8.35 (2H, s)

IR (nujol): 1776 cm⁻¹.

PREPARATION OF THE COMPOUNDS (A) Example 1

To a solution of lithium diisopropylamide, which is prepared fromdiisopropylamine (95 mg), n-butyl lithium (1.5 mol in n-hexane; 0.52 ml)and tetrahydrofuran (2 ml) by a conventional procedure, is addedhexamethylphosphoric triamide (138 mg) at -78° C., followed by dropwiseaddition of a THF solution (5 ml) of a mixture (269 mg) of (2S, 4S)isomer and (2R, 4S) isomer of γ-lactone derivative prepared inPreparation 8. After the mixture is stirred at the same temperature for40 minutes, methyl iodide (185 mg) is dropwise added to the mixture andthe mixture is stirred for additional 2 hours. To the reaction solutionis added a saturated aqueous solution of ammonium chloride and themixture is warmed to room temperature. After extraction with ether (x2),the extract is dried with magnesium sulfate and distilled to remove thesolvent. The residue is purified by silica gel chromatography to giveγ-lactone derivatives, (2S, 4S) isomer (253 mg) and (2R, 4S) isomer (37mg) of the following formulae:

(2S, 4S) isomer: ##STR49##

Phase transfer temperature: ##STR50##

[α]_(D) ²⁷ =+28.15° (c=1.058, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.85-0.98 (6H, m), 1.18-1.73 (19H, m), 2.00- 2.21 (2H,m), 2.62 (2H, t, J=7.70Hz), 4.04-4.17 (2H, m), 4.71-4.80 (1H, m), 6.93(2H, d, J=8.79Hz), 7.21 (2H, d, J=7.33Hz ), 7.44 (2H, d, J=8.06Hz), 7.49(2H, d, J=8.79 Hz)

(2R, 4S) isomer: ##STR51##

Phase transfer temperature: ##STR52##

[α]_(D) ²⁷ =+20.76° (c=1.247, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.86-0.98 (6H, m), 1.27-1.64 (19H, m), 2.03 (1H, dd,J=8.8Hz, J=12.8Hz), 2.35 (1H, dd, J=7.5Hz, J=12.8Hz), 2.62 (2H, t,J=7.3Hz), 4.06-4.18 (2H, m), 4.71-4.80 (1H, m), 6.95 (2H, d, J=8.79Hz),7.22 (2H, d, J=8.43Hz), 7.45 (2H, d, J=8.06Hz), 7.50 (2H, d, J=8.79Hz).

Example 2

In the same manner as described in Example 1 except thatdiisopropylamine (70 mg), n-butyl lithium (1.5 mol/l in n-hexane; 0.30ml), tetrahydrofuran (1 ml), hexamethylphosphoric triamide (100 mg),methyl iodide (130 mg) and a THF solution (2 ml) of a mixture (163 mg)of γ-lactone derivatives, (2R, 4R) isomer and (2S, 4R) isomer preparedin Preparation 6 are employed, there are prepared γ-lactone derivatives,(2R, 4R) isomer (130 mg) and (2S, 4R) isomer (22 mg) of the followingformulae:

(2R, 4R) isomer: ##STR53##

Phase transfer temperature: ##STR54##

[α]_(D) ²⁵ =-25.95° (c=1.013, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.87-1.66 (34H, m), 1.85 (2H, s), 1.88 (2H, s), 2.05 (1H,dd, J=6.96Hz, J=12.45Hz ), 2.17 (1H, dd, J=9.89Hz, J=12.82Hz), 2.42 (1H,t, J=12.09Hz), 4.04-4.15 (2H, m), 4.71-4.81 (1H, m), 6.83 (2H, d,J=8.43Hz), 7.13 (2H, d, J=8.8Hz).

(2S, 4R) isomer: ##STR55##

Phase transfer temperature: ##STR56##

[α]_(D) ²⁵ =-17.15° (c=0.893 CH₂ Cl₂)

NMR (CDCl₃) δ: 0.86-1.59 (34H, m), 1.83 (2H, s), 1.87 (2H, s), 2.01 (1H,dd, J=8.79Hz, J=13.79Hz), 2.34 (1H, dd, J=7.33Hz, J=12.82Hz), 2.41 (1H,t, J=12.09Hz), 4.02-4.12 (2H, m), 4.69-4.78 (1H, m), 6.82 (2H, d,J=8.80Hz), 7.12 (2H, d, J=8.79Hz).

Example 3

In the same manner as described in Example 1 except thatdiisopropylamine (80 mg), n-butyl lithium (1.5 mol/l in n-hexane; 0.41ml), tetrahydrofuran (2 ml), hexamethylphosphoric triamide (130 mg),methyl iodide (170 mg) and a THF solution (5 ml) of a mixture (257 mg)of γ-lactone derivatives, (2S, 4S) isomer and (2R, 4S) isomer preparedin Preparation 9 are employed, there are prepared γ-lactone derivatives,(2S, 4S) isomer (90 mg) and (2R, 4S) isomer (20 mg) of the followingformulae:

(2S, 4S) isomer: ##STR57##

Phase transfer temperature: ##STR58##

[α]_(D) ²⁵ =+29.53° (c=0.993, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.86-0.91 (6H, m), 1.29-1.67 (25H, m), 1.77-1.86 (2H, m),2.07 (1H, dd, J=6.96Hz, J=12.83Hz), 2.20 (1H, dd, J=9.89Hz, J=13.19Hz),4.07 (2H, t, J=6.59Hz), 4.11-4.23 (2H, m), 4.74-4.84 (1H, m), 6.97 (2H,d, J=9.16Hz), 8.29 (2H, d, J=9.16Hz), 8.41 (2H, s).

(2R, 4S) isomer: ##STR59##

Phase transfer temperature: ##STR60##

[α]_(D) ²⁵ =+25.99° (c=0.547, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.86-0.91 (6H, m), 1.15-1.62 (25H, m), 1.78-1.88 (2H, m),2.05 (1H, dd, J=8.79Hz, J=13.19Hz), 2.36 (1H, dd, J=7.33Hz, J=13.19Hz),2.36 (1H, dd, J=7.33Hz, J=13.19Hz), 4.08 (2H, t, J=6.60Hz), 4.10-4.22(2H, m), 4.68-4.82 (1H, m), 6.98 (2H, d, J=8.79Hz), 8.29 (2H, d,J=9.16Hz), 8.42 (2H, s).

Example 4

In the same manner as described in Example 1 except thatdiisopropylamine (70 mg), n-butyl lithium (1.5 mol/l in n-hexane; 0.13ml), tetrahydrofuran (2 ml), hexamethylphosphoric triamide (54 mg),methyl iodide (250 mg) and a THF solution (5 ml) of a mixture (80 mg) ofγ-lactone derivatives, (2S, 4S) isomer and (2R, 4S) isomer prepared inPreparation 8 are employed, there are prepared γ-lactone derivatives,(2S, 4S) isomer (26 mg) and (2R, 4S) isomer (11 mg) of the followingformulae:

(2S, 4S) isomer: ##STR61##

Phase transfer temperature: ##STR62##

[α]_(D) ²⁹ =+15.12° (c=0.823, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.87-0.93 (6H, m), 1.26-1.68 (21H, m), 1.77-1.87 (2H, m),2.09 (1H, dd, J=6.96Hz, J=12.82Hz), 2.22 (1H, dd, J=9.89Hz, J=12.82Hz),4.01 (2H, t, J=6.60Hz), 4.15-4.26 (2H, m), 4.78-4.85 (1H, m), 7.01 (2H,d, J=8.79Hz), 7.03 (2H, d, J=8.79Hz), 7.54 (2H, d, J=8.79Hz), 8.43 (2H,d, J=9.16Hz), 8.93 (2H, s).

(2R, 4S) isomer: ##STR63##

Phase transfer temperature: ##STR64##

[α]_(D) ²⁷ =+7.97° (c=0.483, CH₂ Cl₂)

NMR (CDCl₃) δ: 0.88-0.92 (6H, m), 1.26-1.70 (21H, m), 1.76-1.87 (2H, m),2.06 (1H, dd, J=8.79Hz, J=13.18Hz), 2.37 (1H, dd, J=7.32Hz, J=12.82Hz),4.02 (2H, t, J=6.60Hz), 4.13-4.24 (2H, m), 4.75-4.83 (1H, m), 7.01 (2H,d, J=9.16Hz), 7.04 (2H, d, J=8.79Hz), 7.54 (2H, d, J=8.79Hz), 8.42 (2H,d, J=9.16Hz), 8.93 (2H, s).

LIQUID CRYSTAL COMPOSITION AND ELEMENT FOR OPTO-ELECTRONICS DEVICESExample 5

The (2S, 4S) isomer of the γ-lactone derivative prepared in Example 1 ofthe following formula: ##STR65## and a compound of the followingformula: ##STR66## are mixed together at a weight ratio of 1:21.1 togive a liquid crystal composition.

The obtained liquid crystal composition is measured for phase transfertemperature by DSC measurement and observation with a polarizationmicroscope, and as a result, the composition is found to show thefollowing phase transfer temeperature: ##STR67##

The liquid crystal composition is also measured for response speed usinga cell (thickness of spacer: 2 μm) consisting of two glass substrateswhich are affixed with an ITO membrane, applied with polyimide andsubjected to rubbing treatment, wherein the response speed is measuredby sealing the composition in the cell and measuring a change intransmitted light when the cell is charged with a voltage of V_(p-p) =20V. As a result, it is found that the response speed is 27 μsec (30° C.).

Example 6

The (2R, 4S) isomer of the γ-lactone derivative prepared in Example 1 ofthe following formula: ##STR68## and the compound of the formula (1)prepared in Example 5 are mixed together at a weight ratio of 1:21.2 togive a liquid crystal composition. The obtained liquid crystalcomposition is measured for phase transfer temperature and responsespeed in the same manner as in Example 5 to give the followingmeasurements: ##STR69##

Example 7

The (2R, 4R) isomer of the γ-lactone derivative prepared in Example 2 ofthe following formula: ##STR70## and the compound of the formula (1)prepared in Example 5 are mixed together at a weight ratio of 1:20.4 togive a liquid crystal composition. The obtained liquid crystalcomposition is measured for phase transfer temperature and responsespeed in the same manner as in Example 5 to give the followingmeasurements: ##STR71##

Example 8

The (2S, 4S) isomer of the γ-lactone derivative prepared in Example 3 ofthe following formula: ##STR72## and the compound of the formula (1)prepared in Example 5 are mixed together at a weight ratio of 1:20.4 togive a liquid crystal composition. The obtained liquid crystalcomposition is measured for phase transfer temperature and responsespeed in the same manner as in Example 5 to give the followingmeasurements: ##STR73##

Example 9

The (2R, 4S) isomer of the γ-lactone derivative prepared in Example 4 ofthe following formula: ##STR74## and the compound of the formula (1)prepared in Example 5 are mixed together at a weight ratio of 1:20.0 togive a liquid crystal composition. The obtained liquid crystalcomposition is measured for phase transfer temperature and responsespeed in the same manner as in Example 5 to give the followingmeasurements: ##STR75##

What is claimed is:
 1. A liquid crystalline compound having an opticallyactive γ-lactone ring of the general formula (A):wherein R¹ is a groupselected from the group consisting of ##STR76## n and e are eachindependently 0 or 1, R³ is an alkyl group having 1 to 15 carbon atomsor an alkenyl group having 2 to 15 carbon atoms, said alkyl and alkenylgroups having each optionally one or more asymmetric carbon atoms, X andY are each hydrogen atom, a halogen atom and a cyano group, R² is analkyl group having 1 to 15 carbon atoms or an alkenyl group having 2 to15 carbon atoms, said alkyl and alkenyl groups having each optionallyone or more asymmetric carbon atoms, and * means an asymmetric carbonatom provided that when R² is methyl, the carbon atom at 2-position isnot an asymmetric carbon atom.
 2. The compound according to claim 1,which is in the form of a racemic mixture.
 3. The compound according toclaim 1, wherein R² is an alkyl group having 3 to 8 carbon atoms, R³ isan alkyl group having 3 to 9 carbon atoms, n is 0 or 1, and X and Y areeach hydrogen atom.